The use of seismic techniques to obtain information about subterranean geophysical features is very well-known in the prior art. Such techniques are commonly employed in the exploration for and production of hydrocarbons, e.g, natural gas and oil. The advantages and desirability of accurate characterization of subterranean features are self-evident.
Raw seismic data is typically obtained through the use of a seismic source and receiver. This acquisition may take place on land or in a marine setting. As is known by those of ordinary skill in the art, so-called "processed" seismic data is derived from the raw seismic data by applying such conventional processing techniques as static correction, amplitude recovery, band-limiting or frequency filtering, stacking, and migration. The processed seismic data may be of either the so-called reflection coefficient data type or the integrated trace data type.
Once the processed seismic data has been derived, this data must-be correlated with such physical characteristics as reservoir continuity, reservior thickness, pore fill fluid type (oil, gas, water, etc . . . ), lithologic variation, and pay thickness, to name but a few. This correlation is most commonly accomplished using seismic data (two or three dimensional) in conjunction with electric well logs. Other ways of making this correlation include, e.g., analysis of surface out-crops and statistical modelling exercises.
Three-dimensional seismic data are a 3-D grid of data which are commonly regularly sampled on x-y-z coordinate axes. The subsurface seismic response data may be obtained in any desired conventional manner, e.g., by conducting a seismic survey or by acquiring data generated in a previous seismic survey (e.g., by purchasing the data from a seismic vendor). Three-dimensional data can also be obtained by "regularizing" an irregularly-sampled data set, e.g., a two-dimensional seismic survey.